For some reason, for me, hearing and sight seem to go together. After a long day on the telephone, listening to clients (who are often angry and frustrated by the time they've been transferred to me), I find that my eyes are so tired that they blur and ache when I try to read for a bit before going to bed.

It's not just due to getting older, either. Years ago I volunteered in a Search and Rescue organization as a communications officer, rank of Major. When a search was on, I monitored the radios for three different frequencies, coordinating search teams in the air with search teams on the ground and base personnel centrally located. After a 12 hour day, my ears were ready to fall off, and, to my surprise, my eyes were tired, too, though I had done very little reading or writing during the day.

The reverse is true, as well. After working at the computer and reading reports all day, I find it hard to listen with comprehension to conversation or verbal work reports. They seem to slide by in a blur of noise and afterward I couldn't tell you what was said, to save my life (I take notes as backup). It's especially pronounced when I'm not wearing my glasses.

Maybe vision and hearing use the same parts of the brain; I don't know. All I know is that, for me, when one mode of information acquisition is overworked, the other is mostly nonfunctional, as well. This is true especially when I'm tired after a long day, but even in short bursts, overload of one sense seems to shunt the other to ground.